Combination retort and hearth for stokers



June 1, 1943, c. HEA$LEY 2,320,410

COMBINATION RETORT AND HEARTH FOR STOKERS Filed June 19, 1940 4 Sheet s-Sheet 2 7 mvmoa B 7710/1105 '6. [flees/g ATTOR'NEY June 1, 1943. 1-. c. CHEASLEY 2,320,410

COMBINATION RETORT AND HEM-1TH FOR STQKERS Filed June 19, 1940 4 Sheets-Sheet 3 INVENTOR Thomas C Mew/e av I ATTORNEY June 1, 1943. T. c. CHEASLEY 2,320,410

COMBINATION RETORT AND HEARTH FOR STOKERS Filed June 19, 1940 4 Sheets-Sheet 4 INVENTOR ATTOI'QNEY Patented June 1, 1943 UNITED STATES PATENT OFFICE COMEINATION RETORT AND HEARTH FOR STOKERS 11 Claims.

This invention relates to stokers, and more particularly to a retort and hearth therefor, and has for its principal object to provide a retort with a water jacket for maintaining a relatively low temperature thereof and prolonging life of the section supporting the fuel bed.

Other objects of the invention are to provide the water jacket with ducts for supplying combustion supporting air to the tuyere, whereby the air is admitted through the fuel bed to raise the level of the bed out of the retort chamber; to provide the retort with a water-cooled plate section for preventin sticking of clinkers thereto; and to provide for preheating of the combustion supporting air incidental to delivery thereof through the ducts of the water jacket for increasing efficiency of combustion.

Other objects of the invention are to provide for connection of the retort water jacket with the water legs of a boiler and, in the case of warm air furnaces, to provide means for connecting the water jacket of the retort with the hot water system, thereby conserving the heat absorbed by the water; to provide a retort with water-cooled dead or live plates, as the case may be, adapted to fit individual boilers or furnaces through extension of the plates to the furnace wall leaving only sufficient clearance for expansion and roomfor refractory sealing material; and to provide upward extension of the water-cooled plates for protecting the mud ring of boilers.

In accomplishing these and other objects of the invention, I have provided improved details of structure, the preferred forms of which are illustrated in the accompanying drawings, wherein:

Fig. 1 is a perspective view of a Stoker fed warm air furnace equipped with a retort embodying the features of the present invention.

Fig. 2 is an enlarged vertical section through the retort.

Fig. 3 is a plan View of the retort, parts of which are broken away to better illustrate the construction thereof.

Fig. 4 is a perspective view of parts of the retort shown in disassembled spaced relation.

Fig. 5 is a vertical section through a modified form of the invention showing the water jacket of the retort provided with an upwardly extending leg for protecting the mud ring and water legs of the boiler in which the retort is installed.

Fig. 6 is a further modified form of the invention showing the water legs provided with inward extensions to cooperate with extensions on the water jacket of the retort in forming a dead plate.

Fig. 7 is a section through a. further modified form of the invention showing a retort adapted for an elongated fire-box with the water jacket provided with laterally extending live plates cooperating with dump plates.

Fig. 8 is a section through the form of the invention illustrated in Fig. 7.

Referring more in detail to the drawings:

I designates an ordinary hot air furnace having a fire-bowl 2 supported on a lower section 3 normally constituting the ash-pit of the furnace. The front of the furnace is provided with a door 4 opening into the combustion chamber, and a lower door 5 through which the air and coal ducts 6 and l or a stoker pass to connect the feed hopper and fan (not shown) with the wind-box 8 and retort 9 of the stoker apparatus.

In the illustrated instance, the air-box 8 includes a cylindrical body portion I3 coaxial with the furnace fire-pot and having a substantially rectangular front extension II provided with an opening at one side thereof to connect the air duct 6. The coal duct I, however, projects through the extension and terminates in an upwardly directed outlet member I2, having a flange I3 for seating the upper section of the retort 9. The upper portion of the outlet I2 cooperates with the upwardly diverging annular wall I4 of the retort to provide a substantially conical-shaped retort chamber I5. The wall I4 terminates in a laterally extending annular flange I6 that ordinarily closes the space around the retort to provide a dead plate and a support for a tuyere II concentric with the retort chamber. The tuyere includes a ring having a wall portion I8 conforming in slope to the wall I4 and provided with a plurality of air openings I9. The upper portion of the wall i8 rounds outwardly and downwardly, as at 20, and connects with a wall portion 2| having a laterally extending flange 22 seated upon the plate Iii. The tuyre thus forms an annular manifold in communication with the outlet openings I9 and openings 23 in the plate I6. Coal is delivered from the hopper through the duct 1 by a screw conveyor 24 to maintain the retort chamber full of coal when the stoker is in operation.

The structure thusfar described is equivalent to the corresponding parts of any standard under fed stoker which, if operating satisfactorily, keeps the retort chamber full of fresh fuel with the fire bed above the tuyere. Gas from the coal in the retort is distilled therefrom incidental to the heat of the burning fuel and passes upwardly into contact with the air admitted through the openings IQ of the tuyere so as to maintain the coking fuel in burning condition with the hottest part of the fire extended uniformly over the top of the tuyre. The ash gravitates downwardly over the rounding portion and accumulates on the plate 16 in the form of a clinker. When the rate of feed of fuel and the amount of air delivered are in proper proportions using a good grade of stoker coal, the fire may be satisfactorily maintained, but any stoppage of the fuel fed or with too large amount of air, the fire burns down into the retort and below the level at which the air enters through the tuyere, with the result that the metal wall of the tuyere is excessively heated and soon deteriorates.

With certain types of coal, the coal cakes into a solid mass which arches over the tuyere so that the fire cannot pass therethrough, with the result that the fire burns on the bottom side, around the edges, and down into the retort, causing damage to the retort. Another disadvantage is that the plate supporting the bed of fuel becomes excessively hot and causes the clinkering ash of the so-called low fusion coals to adhere thereto, making it difficult to remove. To overcome these and other difficulties of present stoker mechanisms, I have provided the retort with a water jacket through which water is circulated to maintain a predetermined maximum temperature of the retort. and prevent injury thereto in case the fire should burn therein. I have further provided the plate [6 with a water jacket 26 which. may be formed as a continuation of the water jacket 25, thereby preventing the plate It from heating to the point where the clinker will tend to stick thereto. Cooling of the retort also has the advantage in maintaining the fire at a higher level, and by directing the combustion supporting air through the fuel bed above the water-cooled section, the fuel bed level is kept out of the retort chamber, as now to be described.

The retort constructed in accordance with the present invention is best illustrated in Fig. 2 and the water jacket 25 is formed by providing the base of the retort with a laterally extending flange 2'! which curves upwardly, as at 28, to terminate in an outwardly curved portion 29 spaced below the plate l6 and which connects with a horizontal annular plate portion 30 for closing the space between the retort and the base of the fire-bowl. The plate portion 30 is of smaller diameter than the fire-bowl so as to allow ample contraction and expansion incidental to heating and cooling of the respective parts.

In order to provide a sealing space about the periphery of the water jacket 26, the plate portion l6 preferably terminates short of the plate portion 30 and is connected therewith by an annular, downwardly, and outwardly sloping wall 32 that is spaced from the fire-bowl to accommodate a body of refractory sealing material 33. In order that air from the fire-box may be supplied to the openings IS, the water jacket is provided with tubular ducts 34 connecting the airbox with the openings 23, as best shown in Fig. 2. To provide for circulation of water through the jacket, the wall portion 29 is provided below the base thereof with a boss having an internally threaded opening 35 to connect a water supply pipe 36. After circulating through the water jacket and picking up the heat from the retort and plate It, the water is discharged through a pipe connection 31 having connection with the water jacket section 26. The water may be discharged to a sewer or other place of disposal, but since it contains a considerable amount of heat,

it is desirable to connect the outlet pipe with a hot water supply system (not shown).

In order that the retort, including the water jacket therefor, may be installed through the door 4 of the furnace, it is preferably divided diametrically, as shown in Fig. 4, to form mating sections 38 and 39 having facing walls 40 and 4| provided with registering openings 42 and 43 for maintaining circulation therethrough. The sections are bolted together and interposed with a gasket to provide a tight joint.

With the structure thus described, the wall I4 of the retort is kept in cool condition so that the fire is maintained above the dead plate, the gases being distilled in the retort and mixed with the combustion supporting air admitted through the tuyere. The coal cokes in the upper portion of the retort and is displaced to form the fuel bed by the admission of fresh coal to the bottom of theretortupon operation of the screw conveyor. The ashes from the fuel bed fall over the rounded portionof the tuyere and form a clinker which collects upon the relatively cool surface of the dead plate. The ash is thus readily disposed in the form of clinkers which are free of dust. The combustion supporting air, upon passage through the ducts 34, is preheated to promote combustion of the fuel and efiiciency of the apparatus.

In Fig. 5 the invention is shown as applied to the fire-box of an ordinary fire-tube boiler, and is of substantially the same construction as that previously described, with the exception that the laterally extending water jacket conforms to the rectangular shape of the fire-box. In this instance, the plate 40 constitutes a live plate in that air is admitted therethrough from the windbox through integral ducts 4| and 42. The marginal edge of the lateral portion of the water jacket extends substantially to the inner face of the water leg of the boiler and has an upwardly extending portion 43 which forms a protection for the water leg at the base of the fuel bed and on which the clinkers collect, there being suflicient spacebetween the water jacket and water legs of the boiler to provide for expansion and contraction, and this space is filled with a suitable refractory material as indicated at 44. In thisiorm of the invention, the outlet pipe from the water jacket may be connected with the Water legs of the boiler to promote circulation therein.

In the form of the invention shown in Fig. 6, the lateral wings 45 of the water jacket are relatively short and abut with inwardly extending wings 46 having connection with the water legs of the boiler 41 at a level directly above the mud ring 48, whereby the-inward extension of the water legs cooperates with the outward extension of the retort jacket to form dead plates which support the fuel bed.

In' the form of the invention illustrated in Figs. 7 and 8, I have provided a retort 49 of elongated trough-like shape, extending longitudinally of the central portion of a fire-box 50 and having lateral wing-like water jackets 5| sloping downwardly and outwardly toward the sides of the fire-box to provide live plates on which the fuel bed is supported. The lateral water jackets 5| terminate short of the side Walls 52 of the furnace and cooperate with dump plates 53 whereby the clinkers are discharged into the ashpit of the furnace. Otherwise the modification operates in the same manner as the other forms of the invention previously described.

From the foregoing it is obvious that I have provided protection of the retort of a stoker apparatus so as to avoid overheating thereof, thereby providing a retort of longer life and more efficient operation. It is also obvious that the water-cooled fuel supporting plates control ternperature thereof so as to avoid sticking of the clinkers that result from consumption of the fuel. These clinkers may, therefore, be readily removed by way of the furnace door with the aid of a poker or clinker tongs. While it is necessary to provide for continuous flow of water through the coolingjackets, there is no loss of efficiency or increase in expense of operation as the heated water may be used in the hot water system or admitted to the water legs of a boiler for increasing circulation therein. The watercooled retort and ash-receiving plates will tend to prevent clinker formation when s-o-called high ash fusion coals are burned, and therefore allow for mechanical removal of the ash or refuse automatically, if desired.

What I claim and desire to secure by Letters Patent is:

1. A stoker apparatus including a retort having an imperforate wall for containing a fuel, a jacket surrounding the retort to provide a passageway for a cooling liquid to cool said retort, means for circulating a cooling liquid through said passageway to reduce temperature of the retort, a

tuyere supported above the retort, and an air duct extending through said jacket and having connection with the tuyere for supplying combustion supporting air to the tuyre whereby combination of the fuel is effected above the retort by the air supplied through said tuyere.

2. In an apparatus of the character described, a retort, a fuel bed support associated with the retort, means for circulating a cooling liquid in contact with the retort and said support to control the temperatures thereof, a tuyere carried on said fuel bed support and having .an annular chamber provided with a plurality of air outlet ports, and air ducts extending through said temperature controlling means for supplying air to said annular chamber of the tuyere.

3. In an apparatus of the character described, a retort including mated sections each having an external water-circulating chamber, means securing the sections together, means for circulating water through the chambers of said sections, 5

a tuyere supported on said sections, and air ducts extending through said sections for supplying air to the tuyre.

4. In combination with the fire-box of a furnace, a retort having upper and lower radially extending plate portions, said upper plate portion terminating short of the lower plate portion, a wall connecting the plate portions at said edge of the upper plate portion and adjacent to the edge of the lower plate portion to cooperate with walls of the fire-box in forming an annular groove, a refractory material filling said groove, and means for circulating a cooling medium between said plate portions to control temperature of the retort.

5. In a stoker, a substantially elongated retort having laterally extending wings at the sides thereof and provided with water-circulating spaces, air ducts extending through said wings, a water jacket for the retort and having connection with the water-circulating spaces in said wings, a tuyere carried on the retort, and tubes extending through said water jacket of the retort for delivering combustion supporting air to the tuyere.

6. In a stoker, a substantially elongated retort having laterally extending wings at the sides thereof and provided with water-circulating spaces, air ducts extending through said wings, a water jacket for the retort and having connection with the water-circulating spaces in said Wings, a tuyere carried on the retort, tubes extending through said water jacket of the retort for delivering combustion supporting air to the tuyere, and dump plates cooperating with said laterally extending wings for supporting a fuel bed above said retort,

7. A stoker apparatus including, a water cooled retort, a water cooled dead plate extending laterally of the upper portion of the retort, a tuyere projecting above the retort in encircling relation with the retort and having air outlet openings above the plane of said dead plate to support combustion above the dead plate, and means for supplying air to said tuyere in heat exchange relation with the water used in cooling the retort whereby preheated air is discharged through the outlet openings.

8. In combination with a fire-box of a furnace, a retort having upper and lower laterally extending plate portions, a wall connecting outer edges of the plate portions, said plate portions and wall being of a size to form a groove with walls of the fire-box, a refractory material filling the groove, and means for circulating a cooling medium between said plate portions to control temperature of the retort.

9. In combination withv a fire-box of a furnace, a retort having upper and lower laterally extending plate portions, a wall connecting outer edges of the plate portions, said plate portions and wall being of a size to form a groove with walls of the fire-box, a refractory material filling the groove, means for circulating a cooling medium between said plate portions to control tem-- perature of the retort, a tuyere above said retort, and air supply ducts connecting the plate portions and having outlets discharging into said tuyre.

10. A stoker apparatus including, a water cooled retort to retard combustion in said retort, a water cooled fuel support extending laterally from the retort, a tuyere supported above the fuel support and having air outlets located in upwardly spaced relation with respect to the fuel support for maintaining combustion above the fuel support, and means for supplying air to said tuyere in heat exchange relation with the water used in cooling the retort.

11. A stoker apparatus including, a retort, a fuel support extending laterally of the retort at the upper portion thereof, a tuyere carried on and projecting above the fuel support and having outlet openings located above the retort, a water jacket for the fuel support and retort to prevent combustion within the retort and maintain a relatively low temperature for the fuel support, and ducts extending through the water jacket and having connection with the tuyre to supply combustion supporting air for discharge through said outlet openings.

THOMAS C. CI-IEASLEY. 

